The project examines body fluids secreted into the bronchus and branches of the bronchial tree in the lungs of patients undergoing asthmatic attacks. Fluid obtained by bronchoscopy has been shown to contain a protein factor which activates and produces an inflammatory mediator of the kinin family. It is hoped that it can be shown that all asthmatic subjects have components in the fluid which were capable of activating this inflammatory mediator, and that normal subjects lack it.